Fuels containing amine salts of alkyl acid phosphates



United States Patent Ofiice 322,758 Patented Jan. 11, 1966 3,228,758 FUELS CONTAINING AMlNE SALTS OF ALKYL ACID PHOSPHATES Albert W. Bauer, Wilmington, Deh, assiguor to E. l. du

Pont de Nemours and Company, Wilmington, Del., a

corporation of Delaware No Drawing. Filed Oct. 24, 1961, Ser. No. 147,198

4 Claims. (Cl. 44-72) This is a continuation-in-p-art of my copending application Serial No. 849,177 filed October 28, 1959, now abandoned.

This invention relates to novel amine salts of branched chain primary alkyl acid esters of ortho-phosphoric acid and to distillate hydrocarbon fuels containing them.

It is known that some amine salts of some aliphatic esters of acids of phosphorus can be added to distillate hydrocarbon fuels, such as gasoline and fuel oils, and will be effective therein to inhibit color and haze formation, inhibit rusting or corrosion of metals by the fuels, inhibit the formation of ice in carburetor passageways and the stalling of the engine caused thereby, and improve the fuel in other respects. Some of such amine salts of alkyl phosphates are disclosed by Thompson in Patent 2,297,114 and by Cantrell et al. in Patent 2,863,904. The fuels frequently are in contact with water during storage, transportation and use. Some of the amine salts of alkyl phosphates are extracted from the fuels by such water, whereby their beneficial effects on the fuels are diminished or may be lost altogether. Cantrell et al. disclose that their amine salts of di-oxo-octyl phosphates are resistant to water leaching and hence are superior in this respect to prior amine salts of alkyl phosphates.

It is becoming the general practice to add additives, such as stabilizers, rust inhibitors and the like, to the fuels at the refinery where closer control over the addition can be maintained and, in most cases, this is done in the final fuel-blending operation. As reported in the Oil and Gas Journal, vol. 57, No. 10, March 2, 1959, page 139, the only problem encountered is when the blending stocks have not been freed of strong alkalior spent doctor. In these cases, and when the tank bottom water is materially above a pH of 10, most inhibitors tend to form soaps which may be insoluble in the product and usually result in a reduction in rustproof tendencies. It has been found that the amine salts of alkyl acid phosphates that have been proposed heretofore for additives for distillate hydrocarbon fuels, including the amine salts of di-oxo-octyl phosphates, have poor resistance to extraction from the fuels by aqueous alkali solutions, such as the alkaline water bottoms of refinery storage vessels. Thereby such salts are significantly or largely removed from the fuels prior to the distribution of the fuels to servicestations or ultimate distributors and to the consumer.

It is an object of this invention to provide novel amine salts of branched chain primary alkyl acid esters of orthophosphoric acid. Another object is to provide salts of such class which are normally liquid and are partic' ularly adapted for use in distillate hydrocarbon fuels, are highly soluble in such fuels, show greatly improved resistance to extraction of the additive from such fuels by aqueous alkali solutions, and materially improve the properties of such fuels. A further object is to provide distillate hydrocarbon fuels which contain such novel amine salts. Other objects are to provide new compositions of matter and to advance the art. Still other objects will appear hereinafter.

The above and other objects may be accomplished in accord With this invention which comprises novel, normally liquid neutral amine salts of branched chain primary alkyl acid esters of orthophosphoric acid in which each esterifying alkyl group contains 13 to 16 carbon atoms and the amine is an aliphatic hydrocarbon monoamine of 6 to 24 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom, and distillate hydrocarbon fuels containing from about 0.001% to about 0.03% by weight of such amine salts.

The amine salts of this invention are multifunctional additives in distillate hydrocarbon fuels. They are very soluble in the [fuels and are unusually highly resistant to extraction from the fuels by Water and by aqueous alkaline solutions, whereby the fuel compositions contain ing such salts suffer relatively slight or no diminution in the properties conferred thereon by the added salts when such fuel compositions are brought or maintained in contact with Water or with aqueous alkali. Thus, a gasoline, which is normally prone to form gummy deposits during ordinary carburetion, will, after being treated to contain a small amount of the amine salts of this invention, show a markedly lesser tendency to form such deposits in use. Also, a gasoline, which is prone to form ice in the carburetor passageways which impedes or blocks the fiow of air or fuel and causes the engine to stall, will show unusually improved anti-stalling properties when it contains a minor proportion of a salt of this invention. Further, gasoline or other distillate hydrocarbon fuel, which in its normal handling and storage is in con tact with ferrous metal surfaces of pipelines and vessels, can be rendered substantially non-corrosive to said .fer rous metal surfaces by incorporating therein an amine salt of this invention. In addition, since the amine salts of this invention are normally liquid and are readily soluble in the distillate hydrocarbon fuels, they are easily handled and have little or no tendency to crystallize or separate out as a tacky solid phase from their solutions in the fuels. Therefore, the novel salts of this invention are particularly valuable as anti-stalling agents, i.e. anti-icing agents, for gasoline. At the same time, the salts of this invention function as rust inhibitors and detergents in the fuels during storage and in the induction system of the engine.

The amine salts of this invention may be prepared according to any of the methods of the art, by neutralizing primary alkyl acid phosphates, wherein the primary alkyl groups have from 13 to 16 carbon atoms in branched chain configuration, with aliphatic hydrocarbon monoamines containing a total of from 6 to 24 carbon atoms. Normally, a molecule of amine is used for each molecule of monoalkyl dihydro-gen phosphate and for each molecule of dialkyl hydrogen phosphate, to produce a salt exerting a substantially neutral pH (6-7).

The branch chain primary alkyl acid esters of orthophosphoric acid (acid phosphates) will be understood to be those esters in which only 1 or 2 of the three acidic hydrogen atoms of orthophosphoric acid have been replaced by the alkyl groups, i.e. the monoalkyl dihydrogen phosphates and the dialkyl hydrogen phosphates. Such esters may be obtained according to the general methods of the art which involve reacting an alcohol with phosphorus pentoxide (P 0 From about 2 to about 4 moles of the alcohol may be used per mole of P 0 Preferably, about 3 moles of the alcohol per mole of P 0 will be used to yield approximately equimolar mixtures of the monoand dialkyl esters of orthophosphoric acid, containing about 40 to about mole percent of the monoalkyl esters and about 60 to about 40 mole percent of the dialkyl esters. These mixtures of monoand dialkyl esters are preferred for reasons of economy but other mixtures, as well as the single monoalkyl esters and single dialkyl esters, may also be used.

For the prepartion of the branched chain primary alkyl acid phosphates, the alcohol will be a branched chain primary alkanol having 13 to 16 carbon atoms or a mixture of two or more of such alkanols. These alcohols preferably will be the branched chain primary alkanols made by the well-known Oxo process from C0, H and a branched chain olefin such as the C C monoolefinic polymers and interpolymers of propylene and butylene, as described for example by Smith et al. in US. Patent 2,824,836, and by Rudel et al. in US. Patent 2,884,379. Examples of preferred Oxo-alcohols that may be used are branched tridecyl primary alcohols RCH CH CHRCH OH For example, 2-hexadecanol-1 is produced by heating n-octanol with caustic and Zinc dust, as described by Carter in US. Patent 2,457,866. Other alcohols, that may be prepared by the latter and other methods known in the art and used to prepare phosphates according to the present, are of the formula where R is the same or different alkyl group, each having from 4 to 8 carbon atoms and together totalling at least 9. The branched alcohols may also be prepared by the conventional aldolization of suitable aldehydes followed by hydrogenation. In this way, the well-known oxo -octaldehyde, which is obtained from heptene-l, CO and H and which is a mixture consisting very largely of dimethylhexaldehydes, ethylhexaldehydes, and methylheptaldehydes containing the grouping CH CH=O, is converted into 2-hexyldecanol, R'CHRCH OH, where R stands for C alkyl groups such as dimethylbutyl, methylpentyl, and ethylbutyl, and R stands for C alkyl groups such as dimethylhexyl, ethylhexyl and methylpentyl groups.

The amines that are used to produce the novel salts of this invention are the aliphatic hydrocarbon monoamines containing a total of 6 to 24 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom. The term aliphatic hydrocarbon monoamine will be understood to mean a compound which contains only one amino nitrogen to which is attached 1 to 3 aliphatic hydrocarbon radicals. Thus, the amines may be primary, secondary, or tertiary amines, with the primary amines usually being preferred. Usually, the water-insoluble amines will be preferred. The aliphatic hydrocarbon radicals attached to the nitrogen may be acyclic (open chain) or alicyclic (cycloaliphatic) radicals. Also, the aliphatic hydrocarbon radical may be a saturated or an unsaturated radical, provided that the carbon atom which is attached to the nitrogen atom is a saturated carbon atom, that is, a carbon atom that is not attached to another carbon or to the nitrogen by a multiple bond. Preferably, the amine will be an alkyl (acyclic, saturated) monoamine of 6 to 24 carbon atoms and most preferably of 8 to 18 carbon atoms. Also, preferably, when the amine is a secondary amine, it will contain a total of at least 8 carbon atoms and, when it is a tertiary amine, it will contain a total of at least 10 carbon atoms.

Examples of suitable primary amines are: hexylamine; cyclohexylamine; octylamine; 2-ethylhexylamine; laurylamine; hexadecylamine; t-dodecylamine; octaamine and dicyclohexylamine.

tertiary amines are: tributylamine, trihexylamine, triisooctylamine, N,N-diethylcyclohexylamine, N,N-dimethylstearylamine, and N,N-dimethyloleylamine.

Any of the above amines may be employed in salt formation with any of the above branched chain alkyl acid phosphates. Preferred, however, are 2-ethylhexylamine, t-dodecylamine, cocoamine, the mixed t-alkyl primary amine fractions containing 12 to 14 carbon atoms, t-octylamine and t-nonylamine.

It should be noted that the preferred amines employed according to the invention are water-insoluble and oilsoluble. Highly water-soluble amines, such as the lower alkylamines and ammonia which are liberated as the free base when the fuel composition containing the amine salt is contacted with alkali, tend to promote corrosion of copper and brass and thus are undesirable salt components. Further, the salts of these lower amines tend to be objectionably crystalline and show limited fuel solubility.

Also, it is important that the alkyl groups of the phosphate esters be branched chain and have at least 13 carbon atoms. Comparable amine salts of the alkyl phosphates whose alkyl groups have less than 13 carbon atoms, whether in straight or branched chain configuration, tend either to be rather easily extracted into aqueous alkaline solutions or to form hazy precipitates or fuel-insoluble scums when their fuel solutions are contacted with aqueous alkali. Straight chain alkyl groups of more than 12 carbon atoms tend to render the amine salts of their phosphate esters relatively higher melting and diflicultly soluble in the hydrocarbon fuels. Such rather poor solubility make the amine salts of the long straight chain alkyl phosphates particularly unsuitable as additives, e.g. as anti-icing agents in gasolines. Since the amine salts as a class are substantially non-volatile, it is essential, when they are used in gasolines, that they be able to flow freely along the induction system of the engine, through the carburetor particularly, without separating out as solid or semi-solid tacky deposits. It has been found that the amine salts of the present invention, when used in gasolines, are much superior anti-icing agents in respect to the analogous salts of the long straight chain alkyl phosphates.

The distillate hydrocarbon fuels, which are improved by the novel amine salts of this invention, are the normally liquid fuels which include straight-run and cracked gasolines, and hydrocarbon fuel oils such as kerosene, kerosene based jet fuels such as IP-4 and IP-5, diesel fuels, furnace oils, and stove oils, preferably the hydrocarbons boiling in the gasoline boiling range.

The amine salts of this invention ordinarily will be dissolved in the fuel in a concentration of from about 0.001% to 0.03% by Weight of the fuel, preferably about 0.005% by weight. Since each of such salts is a viscous liquid at ordinary room temperatures, e.g. 75 F., and is freely soluble (i.e. miscible in all proportions or very nearly so) in liquid hydrocarbons, they may be readily incorporated homogeneously in the distillate hydrocarbon fuel simply by mixing and agitating. The amine salts may also be handled and added to the fuel as a concentrate, e. g. about 40% to about by weight, in a carrier solvent such as tolu- Examples of A suitable ene, xylene, kerosene, isopropyl alcohol, xylenol, eresol, or mixtures of two or more thereof, if desired, and they frequently will be so added because of the difiiculty of accurately measuring or metering the relatively small amounts of the salts required. Also, small amounts of such solvents may be added to the amine salts to incease their fluidity, because a relatively small amount of the solvent will greatly increase the fluidity of the salts.

The distillate hydrocarbon fuels, containing the amine salts of this invention, may also contain other additives normally associated with the finished fuels, such as metal deactivators, represented by N,N"disalicylidine-l,2-propane diamines; antioxidants, represented by 2,6-ditertiarybutyl-p-cresol and N,N-=disecondary-butyl p phenylene diamine; and antiknock compositions such as tetraethylead or other organolead compounds, together with halohydrocarbon scavenging agents for the lead.

In order to more clearly illustrate this invention, preferred modes of carrying it into eifect and the advantageous results to be obtained thereby, the following examples are given, in which the parts and proportions are by weight except where specifically indicated otherwise.

EXAMPLE 1 Preparation of amine salts A. MIXED MONO- AND DLALKYL PHOSPHATES 142 grams (1 mole) of P was gradually stirred into 600 grams (3 moles) of Oxo-tridecyl alcohol. During the addition of the P 0 the temperature was allowed to rise to 65 C. and held thereabouts by external cooling. After the addition of the P 0 was completed, the reaction mass was stirred at about 65 C. for- 12 hours, when it was shown by potentiometric titration to consist essentially of an approximately 1:1 molar mixture of mono-Oxo-tridecyl dihydrogen phosphate and di-Oxo-t-ridecyl monohydrogen phosphate.

B. NEUTRALIZATION WITH AMINE To the reaction mass, prepared under A, was added dropwise 258 grams (2 moles) of Z-ethylhexylamine, with the temperature kept below 65 C., to produce the mixed Z-ethylhexylammonium monoand di-Oxo-tridecyl phosphates as a viscous amber oil.

Alternatively, the amine may be added as a kerosene (or other solvent) solution, whereby the above amine salt is obtained as a freely mobile solution, e.g. 80% by Weight, in kerosene.

Repeating the above procedures A and B with 2-hexyldecanol-1 (3 moles per mole of P 0 yields the corresponding mixed Z-ethylhexylamine salts of the mixed mono and di-branched chain 2-hexyldecyl esters of orthophosphoric acid as a viscous oil.

Still other amine salts which have been prepared by the above procedures A and B and which constitute additional preferred compositions of this invention are: (l) the mixed t-C -C alkyl primary amine salts of the approximately equimolar mixture. of mono.Oxo.-tridecyl.

phosphate and di-OXo-tridecyl phosphate prepared from the commercial mixture of such amines; (2) the mixed t-nonylamine salts of the approximately equimolar mixture of mono-Oxo-tridecyl phosphate and. di-Oxo-tridecy1 phosphate prepared from commercial t-nonylamine; (3) the mixed di-n-butylamine salts of the approximately equimolar mixture of monoand di- Oxo-tridecyl phosphates; (4) the mixed tri-n-butylamine salts of the approximately equiniolar mixture of mono- Oxo and di-Oxo tridecyl phosphates; and (5 the mixed tri-n-butylamine salts of the approximately equimolar mixture of monoand di-Z-hexyldecyl phosphates.

The mixed esters specifically referred to above are. all viscous liquids at normal room temperatures and are hi ghly soluble in liquid hydrocarbons (including distillate 11ydrocarbon fuel), alcohols, and phenols. They also show particularly marked resistance to extraction from their solutions in hydrocarbons by Water and by aqueous alkali solutions.

Alternately, procedure A may be employed for any of the branched chain primary alkanols having from 13 to 16 carbon atoms described earlier, to produce approxi mate-1y equimolar mixtures of the corresponding monoand di-branched chain primary alkyl phosphates. Also, instead of the amines of Example 1, any of the amines described earlier may be used in procedure B, to prepare the fuel soluble, alkali resistant amine salts of this invention.

EXAMPLE 2 Anti-rust performance The amine salts of the branched chain alkyly phosphates of this invention are superior anti-rust agents in a Wide variety of distillate fuels. This is demonstrated with representative mixed salts prepared as described in Example 1, employing the Turbine Oil Anti-Rust Test asdescribed by the ASTM method D665 or it close approximation, Military Specification MIL-1250 17.

MINIMUM CONCENTRATION OF PHOSPHATES TO GIVE RUST-FREE SPECIM'ENS [Using synthetic sea water] The efiect of branched vs. straight chain structure on anti-icing performance The superior performance of the branched chain structure over the straight chain structure in the amineneutralized alkyl phosphates is demonstrated by comparison of the anti-icing performance of alkylarnmonium hexadecyl phosphates differing only in the carbon configuration of the phosphate substituent alkyl groups.

The mixed Z-ethylhexylammonium salts of the mixed phosphate esters of n-hexadecyl alcohol and of a commercial hexadecyl alcohol described as a highly branched 2-hexyldecanol, were prepared by the process described in Example 1. These products were tested in a motor gasoline wihch was characterized by a 50% distilled point (ASTM method D86) of 200 F. and caused severe icing in the test engine. The test method is the Carburetor Icing Test described below.

THE EFFECT OF STRUCTURE vON ANTI-ICING PERFORMANCE Minutes of operation to induce Fuel. stall Base gasoline only Base plus 15 lbs./ 1000 b'bls. of 2ethylhexyl ammonium n-hexadecyl phosphates 1 /4 Base plus 15 lbs/1000 bbls. of Z-ethylhexylammonium Z-hexyldecyl phosphates 2 /2 Carburetor icing fest (Chevrolet engine) SCOPE 7 TEST CONDITIONS Intake air F 3840 Relative humidity percent 100 Engine load horsep-ower 10 Engine speed r.p.rn 1,500 Idle speed r.p.m 450-500 'Fuel temperature to carburetor F 4850 Air/ Fuel ratio 12.312.5

Appr-oxlmately.

APPARATUS Standard 6-cylinder Chevrolet engine Horsepower rating, 86 at 3400 r.p.m.

Displacement, 216.5 cu. in.

DESCRIPTION OF TEST All runs are started with the throttle plate at a temperature of 34 F. The engine operating cycle depends on the ice-forming characteristics of the fuel. Run are usually in the 0.5 1.5-minute range for uninhibited base fuels. At the end of the 1500 r.p.m. operating cycle, the throttle is cut back to idle position. If no stall occurs, the engine is allowed to idle for 30 second-s, and the cycle repeated.

EXAMPLE 4 Resistance to extraction by alkali The data tabulated below show the resistance to extraction by both aqueous acids and alkalis of the mixed Z-ethylhexylammonium Oxo-tridecyl phosphates (prepared as described in Example 1) dissolved in gasoline in a concentration corresponding to 0.005% by weight of the fuel. Given for comparison is the behavior of the analogous mixed Z-ethylhexylamine salt-s of the approximately equimolar mixture of monoand di-Oxo-octyl phosphates which were prepared by the same procedure described in Example 1 for preparing the mixed salts of the Oxo-tridecyl phosphates. The test procedure consisted of shaking the gasoline solution for 5 to minutes with 1 vol. percent of an aqueous solution buffered to pH 4 to 11 as given below, allowing the phases to stratify and sit for 3 days, and then determining the amount of phosphorus remaining dissolved in the fuel solution. The phosphorus content is expressed below as percent of the original. The water solutions used for the extractions were buffered below pH 7 with acetic acid-sodium acetate, above pH 7 and up to pH 10 with boric acid-borax, and above pH 10 with sodium bicarbonate-sodium carbonate mixtures.

PERCENT PHOSPHORUS REMAINING IN GASO- Also, it should be noted that, on contacting with water above pH 10, the fuel solution containing the octyl compound became hazy and the analysis less exact.

The above data clearly show the superiority of the salts of the Oxo-tridecyl phosphates over the salts of the 0x0- octyl phosphates in resisting extraction by aqueous solutions, particularly by aqueous alkali.

EXAMPLE 5 The extraction procedure described in Example 4 was repeated, employing 1 vol. percent of 0.1 N aqueous Na CO (pH about 11.5) on isooctane containing 0.005% by weight of the mixed primary amine salts tabulated below. Except for the mixed cocoamine salt, which was prepared by the procedure given by Cantrell et al., in US. Patent 2,863,904, each of the mixed amine salts was prepared as described in Example 1. The results are expressed as percent phosphorus remaining in solution in the isooctane after 3 days.

PERCENT REMAINING PHOSPHORUS IN ISOOC- TANE AFTER SODIUM CARBONATE EXTRACTION Amine Alkyl group of Percent P phosphate Remaining Z-ethylhexyl Oxo-oetyl Less than 10. cocoamine do About 40. t-Cn-Cn alkyl- 0 Less than 10. 2-ethylhexyl 74. t-Cn-Ou alky d0 75. 2ethylhexyl Zhexyldecyl .1 77.

*Commercial mixture of t-alkyl primary amines of 12 to 14 carbon atoms.

The above data again indicate the marked superiority of the salts of the branched alkyl esters of the present invention in resisting extraction by alkaline water.

EXAMPLE 6 These salts were prepared by mixing the appropriate amine and alkyl phosphate and diluting with kerosene to provide solutions containing active ingredients. The oxo-tridecyl phosphates were prepared by the method disclosed in Example 1 of the above-identified application. The di-Z-ethylhexyl phosphate was a commercial product. The di-oxo-octyl phosphate was prepared by the method disclosed by Cantrell et al., in Patent 2,863,904.

The extraction tests were carried out by making up solutions of the salts in purified isooctane to give a concentration of 2 milligrams of phosphorus per liter of solution, agitating the solution with 1 volume percent of 0.1 N aqueous sodium carbonate solution, and allowing the mixture to stand for 3 days at room temperature. The water bottoms, at the end of the 3 days, had a final pH of 11.1. Also, at the end of the 3 days, the water layer was analyzed for phosphorus, and the percent of the phosphorus remaining in solution in the isooctane was calculated by difierence. The results are shown in the following table:

Phosphorus in the water Percent phosphorus re- Salt layer, miclrogramlmillimaining in the isooctane The foregoing tests show that the salts of the oxo-tridecyl phosphates, A and B, are far more resistant to extraction by strong aqueous alkaline solutions than are the salts of-the other alkyl phosphates, C, D and E. The salts, A and B, differ from the salts of Examples 4 and 5 in the amine but exhibit the same order of resistance to extraction by strong aqueous alkaline solutions. The salt C, dimethvlaniline salt of di-Z-ethylhexyl phosphate, is a representative salt of the prior art and is clearly inferior to the salts of this invention. When the dimethylaniline of salt C is replaced by cocoamine as in salt D, the salt is still far inferior to the salts of this invention. See also the results with the cocoamine salt of the oxo-octyl phosphate in Example 5, and compare both with salt B which is the cocoamine salt of alkyl phosphates of this invention. Salt E, the oleyl ammonium di-oxo-octyl phosphate, is another representative salt of the prior art, but such salt E is clearly inferior to the other salts, including the oleyl ammonium salt A of this invention.

Substantially the same order of results are obtained by the methods of the above examples in other hydrocarbon media, including kerosene, ]P-4 and IP5 jet fuel, diesel fuel, stove oil and furnace oil.

It will be understood that the preceding examples have been given for illustrative purposes solely and that this invention is not limited to the specific embodiments described in such examples. On the other hand, it will be readily apparent to those skilled in the art that, subject to the limitations set forth in the general description, many variations can be made in the amine salts, in the mixtures of amine salts, in the distillate hydrocarbon fuel compositions, and in the processes and techniques employed without departing from the spirit or scope of this invention.

From the preceding description, it will be apparent that this invention provides novel amine salts and mixtures of amine salts of branched chain primary alkyl phosphates which have unusual beneficial properties and which are particularly adapted for use in distillate hydrocarbon fuels, particularly for such fuels as may be brought into contact with water or aqueous alkali solutions. Also, this invention provides distillate hydrocarbon fuel compositions containing such novel amine salts which fuels have thereby had their properties greatly improved and will retain such improved properties even when subjected to contact with aqueous alkali solutions over extended periods of time. Accordingly, it is apparent that this invention constitutes a valuable advance in and contribution to the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A gasoline containing from about 0.001% to about 0.03% by weight of a normally liquid neutral amine salt of an oxo-alkyl acid ester of orthophosphoric acid in which each esterifying oxo-alkyl group contains 13 to 16 carbon atoms and the amine is an aliphatic hydrocarbon mono-amine of 6 to 24 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom.

Z. A gasoline containing from about 0.001% to about 0.03% by weight of a normally liquid mixture of neutral amine salts of a mixture of oxo-alkyl monoesters of orthophosphoric acid and oxo-alkyl diesters or orthophosphoric acid in which esters each esterifying oxo-alkyl group contains 13 to 16 carbon atoms and the amine is an aliphatic hydrocarbon monoamine of 6 to 24 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom.

3. A gasoline containing from about 0.001% to about 0.03% by weight of a normally liquid mixture of neutral amine salts of a mixture of about 40 to about mole percent of oxo-tridecyl monoesters of orthophosphoric acid and about 60 to about 40 mole percent of oxo-tridecyl diesters of orthophosphoric acid in which the amine is an aliphatic hydrocarbon monoamine of 6 to 24 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom.

4. A gasoline containing from about 0.001% to about 0.03% by weight of a normally liquid mixture of neutral Z-ethylhexylamine salts of a mixture of about 40 to about 60 mole percent of oxo-tridecyl monoesters of orthophosphoric acid and about 60 to about 40 mole percent of 0x0- tridecyl diesters 0f orthophosphoric acid.

References Cited by the Examiner UNITED STATES PATENTS 2,297,114 9/1942 Thompson 44-69 2,413,852 1/1947 Turner 252-389 2,863,742 12/1958 Cantrell et a1 44-72 2,863,746 12/1958 Cantrell et al. 44-72 2,863,904 12/ 8 Cantrell et al 252-389 3,032,973 5/1962 BisWell et al 44-72 3,079,339 2/1963 Cantrell et al. 44-56 DANIEL E. WYMAN, Primary Examiner. 

1. A GASOLINE CONTAINING FROM ABOUT 0.001% TO ABOUT 0.03% BY WEIGHT OF A NORMALLY LIQUID NEUTRAL AMINE SALT OF AN OXO-ALKYL ACID ESTER OF ORTHOPHOSPHORIC ACID IN WHICH EACH ESTERIFYING OXO-ALKYL GROUP CONTAINS 13 TO 16 CARBON ATOMS AND THE AMINE IS AN ALIPHATIC HYDROCARBON MONOAMINE OF 6 TO 24 CARBON ATOMS IN WHICH EACH ALIPHATIC HYDROCARBON RADICAL IS ATTACHED TO THE NITROGEN THROUGH A SATURATED CARBON ATOM. 